Just spent 3 days on the North Umpqua Trail. We rode on nearly every type of trail surface -- hardpack, wet rocks, jagged rocks, loose scrabble, loose over hardpack, just about everything except slickrock. I was real happy with this tire combination on my Lurcher:

Front -- On One Chunky Monkey 2.4 (single compound), with a tube

Rear -- Geax Gato 2.3, tubeless with Stan's liquid

Great traction, not too much rolling resistance, good grip on rocks and roots, a little cush at low pressures. Definitely not for weight weenies, but it worked well for me.

On One Chunky Monkey
Nice AM 29er tire combo-imageuploadedbytapatalk1370227182.596108.jpg

Geax Gato
Nice AM 29er tire combo-imageuploadedbytapatalk1370227197.729728.jpg